Circuit breaker lighter



a r 1958 P. E. ASHTON ETAL 2,4859% CIRCUIT BREAKER LIGHTER Filed Oct. 9,1956 2 Sheets-Sheet l ATTORNEY/5'.

Aug. 19, 1958 P. E. ASHTON ET AL 9 5 CIRCUIT BREAKER LIGHTER Filed Oct.9, 1956 2 Sheets-Sheet 2 ATTORNEYS.

United States Patent CIRCUIT BREAKER LIGHTER Philip E. Ashton and ArthurW. Schnick, Meriden, Conn., assignors to Cuno Engineering Corporation,Meriden, Conn., a corporation of Connecticut Application October 9,1956, Serial No. 614,948 Claims. (Cl. 219-32) This invention relates toelectric cigar lighters of the type generally used in automobiles, motorboats, aircraft and the like.

Almost all cigar lighters of the class above mentioned comprise a plugwith a heating element having terminals, and a holder or socket havingterminals connected to a source of electrical energy and arranged tocooperate with the terminals of the plug, the socket being suited forboth storing and energizing the plug. Typical constructions, of whichsome millions are made and sold each year, are shown in United StatesPatents Nos. 2,495,657 and 2,531,901.

In these lighters, the plug is normally carried in the socket in astorage or open circuit position with its terminals separated from the,co-operable terminals of the socket so that no current fiows through theheating ele ment. When it is desired to use the lighter, the plug ismoved further into the socket so that a terminal on the plug is engagedand held by a thermostatic, latch-like terminal in the socket againstthe force of a spring adapted toreturn theplug to its storage position.Upon the heating element attaining a predetermined and suitabletemperature, the thermostatic latch-like terminal relinquishes its holdon the plug terminal and the plugthem moves to storage position whenceit may be removed by the user for use, as is well known to those versedin the art. Normally, the time required to bring the heating element toits predetermined. temperature (a bright red heat) is around tenseconds, current consumption being about 100 watts.

Obviously, as the heating element attains red heat in such a short timeit may be. greatly overheated, with an attendant possibility of fireifthe circuit is held closed for a relatively prolonged period, as issometimes. done by an absent-minded user or by the accidentaldisplacement of a piece of luggage or the like whichmay lean against thehandle, of the plug and pressitinto closed circuit position. There is afurther potential danger in that when the plug is out of the socket thelatter is open for the ingress of forei objects such as nails or smallcoins, etc., which may be and have been inserted by children and whichcan cause a short circuit.

While unhappy events of this nature are relatively rare the potential,hazard of fire in an automobile or motor boat or aircraft is such thatthe question of protection-cannot be ignored and much serious thoughthas been given to means to avert such danger.

Proposals have been made to provide a destructible fuse or a circuitbreaker that would open circuit in the event of excessive heat orcurrent in the lighter. Some of these devices were objectionable in thatthey were lo cated in the plug and aiforded no protection against shortcircuit within the socket. Others were complex, expensive and difficultto manufacture. In still other cases the protective device was solocated on the socket as to require that the wiring be disconnectedbefore the fuse could be replaced or the circuit breaker be re-set toclosed circuit condition.

Patented Aug. 19, 1958 Constructions which, as indicated above, requirethat the wiring be disconnected to replace the fuse or reset the circuitbreaker commonly defeat their own purpose and create a further hazard asthe user frequently either will by-pass the protective device or willuse matches instead of the lighter and so, in either event, exposehimself and others to unnecessary risks.

Accordingly it is an object of the present invention to provide a socketfor a cigar lighter of the type described and which incorporates acircuit breaker which cannot be electrically by-passed.

A further object is the provision of a socket for an electric cigarlighter of the type described which socket embodies a protective circuitbreaking device resettable to its normal current carrying conditionwithout disconnection from its electrical supply source of the removalof any parts or the use of any tool.

Yet another object of the present invention is the provision of acombined cigar lighter socket and resettable protective circuit breakerwherein the means for restoring the circuit breaker to current carryingcondition is an integral part thereof having an external part directlyaccessible for manual manipulation. A

Other objects will become apparent on perusal of the appended drawingsand this specification.

Referring to the drawings:

Figure l is a longitudinal section of a cigar lighter socket embodyingthe principles of the present invention and showing the parts in theirnormal current carrying position;

Figure 2 is a partial sectional view generally similar to Figure l butshowing the circuit breaker parts in their open circuit position;

Figure 3 is a front elevation of the socket but partially in sectionalong line 33 of Figure 2;

Figure 4 is a rear elevation of a major subassembly of the circuitbreaker;

Figure 5 is a sectional side elevation of the structure shown in Figure4;

Figure 6 is a front elevation of the circuit breaker armg Figure 7 is across-section of the part shown in Figure 6 and taken along the line 7-7thereof;

Figure 8 is a side elevation of the bracket of the circuit breaker;

Figure 9 is a plan view of the bracket;

Figure 10 is a front elevation of the bracket;

Figure 11 is a sectional View, generally similar to a portion of Figurel and showing another major subassembly of the circuit breaker.

The cigar lighter socket described herein comprises a substantiallycylindrical tubular metallic receptacle lr'l having a bezel 12 at itsfront end and also having screw threads 14 which in cooperation with atubular clamping element of conventional design (not shown) are suitedto secure the socket to the instrument panel of an automobile or-thelike. The wall of receptacle 10 may have lancings l6 affording springfingers 18 adapted to yieldinglyhold a suitable plug carried therein. Inaddition to its mechanical functions the said wall usually serves as agrounded terminal for the circuit supplying electricity to the cigarlighter for heating the heating element thereof. The foregoing structureis not new and is of a well known form, being employed in almost allautomobiles currently being made in the United States.

In addition to the above mentioned well known parts, the socketcomprises a novel circuit breaker conveniently made of twomajorsubassemblies generally designated A and Bin the drawings andpermanently embracing within its organization the whole of the live orungrounded current carrying parts of the socket.

The subassembly shown in Figure l and designated A comprises a housing20 preferably made of a cylindrical metallic shell with an end wall 22having a substantially central opening 24. It also includes a terminalmember 26, a stop member 28, insulating washers 38 and 32, a circuitbreaker thermostat 36 and metallic washers 38 all arranged and securedin the relative positions clearly shown in Figures 1, 2, 3 and ll. Arivet 34 passes through all of these parts and secures them together.The rivet fits snugly in the central hole of insulating washer 38, whichin turn fits closely inside the housing 20. The opening 24 isconsiderably larger than the rivet 34, so that the latter is thussupported by but insulated from the housing 20. The terminal member 26is most conveniently made of bi-metallic thermostatic material andprovided with one or more arms 40, shaped for latch-like and electricalengagement with the heating unit cup of a conventional cigar lighterplug indicated by broken lines in Figure 1. The metallic stop member 28is contiguous with the terminal member 26 and in electrical engagementtherewith and serves to limit the inward travel of a cigar lighter plug.It also affords an auxiliary terminal suited to energize the cigarlighter plug element, if desired, when the arms 40 are warped to a plugreleasing position by the heat of the heating element. Both terminal member 26 and stop member 28 are generally U-shaped and have their baseportions pierced to fit closely on rivet 34 and are located thereon bycollar 35 which is insulated from end wall 22 by insulating washer 32,also pierced to closely fit rivet 34. The circuit breaker thermostat 36is preferably made from a flat strip of thermally responsive bi-metalbent into a rough L-shape and provided with a tail 42 suited for keyingengagement with suitable apertures 29 in insulating washers 38 and 32while having no contact with the walls of a clearance opening 23 in endwall 22; the base portion of the thermostat 36 also has a hole affordinga close fit for rivet 34 which in conjunction with the tail 42 serves toprevent relative movement of the mutually engaging parts.

The receptacle 10 has a reduced diameter portion 11 in which the housing20 is supported and secured in place by any suitable means, preferablyspot welding. The receptacle 10 also has one or more portions of itswall depressed radially inward, as shown at 44 in Figures 1 and 3, toafford a key for engagement with insulating washer 32 which has itsperiphery suitably notched at 33 for this purpose and which is a closefit on the inner surface of receptacle 10. The terminal member 26 andstop member 28 may also preferably have portions affording keyingengagement with insulating washer 32. Metallic washers 38 are arrangedat each end of rivet 34 as shown in Figure 1, so that they serve toprevent the distortion of parts adjacent them when the ends of rivet 34are being riveted over. The keying engagement of insulating washer 32with the key portion 44 of receptacle 10 together with the weldingtogether of housing 20 and reduced diameter portion 11 provides meanswhereby all components heretofore described may be interlocked againstrelative motion.

The subassembly shown in Figures 4 and and designated B comprises a disc46, a conductive bracket 48, a

circuit breaker arm 50 a tension spring 52, a reset plunger 54 and aterminal stud 56. The disc 46 is most desirably made of an insulatingmaterial such as a phenolic impregnated laminated fabric and may haveits periphery notched as at 58 for keying and supporting engagement witha suitable series of fingers 60 formed at the open end of housing 20 andsuited to be bent over onto said disc to secure it in place as shown at61 in Figures 1 and 2. As shown in Figures 8, 9 and 10, the bracket 48,most conveniently made of sheet metal, has a base portion 62 pierced byhole 64 and is secured to disc 46 by means of terminal stud 56 whichpasses through a suitable hole in said disc and also through hole 64 andis riveted as at 66 to firmly secure the parts together. A tongue 68,integral with the bracket 48 and which is provided by metal displaced inlancing the opening 70 passes through a suitable opening 72 in disc 46and is bent over as shown in Figures 5 and 4 to prevent relativerotation of disc 46 and bracket 48 on stud 56. In addition to the baseportion 62, the bracket 48 also comprises a support portion 74 having anopening 70, a guideway 76, and a spring retaining hook 78. The opening70 is stepped in width, the narrowest part 71 furnishes the metalnecessary for tongue 68 and has no other function, the next widerportion 80, affords an edge 81 serving as a fulcrum or pivoting edge forcircuit breaker arm 50 and also affords the margins 82 for cooperationwith notches 51 in arm 50 to retain the latter in its desired location;the widest portion of the opening 70 aifords a passage through which arm50 may be inserted during assembly of the device as will be more fullyexplained below. The guide way 76 is defined by bending parts of theedges of the bracket into oppositely facing L-shapes and therebyproviding a short substantially rectangular tubular portion to serve asa guide and support for reset plunger 54, which also passes through andis further guided by opening 72 in disc 46.

The circuit breaker arm 50 is shown in Figures 6 and 7 and is preferablymade of sheet metal such as brass or bronze. As is apparent by acomparison of the positions of this part in Figures 1 and 2, it has arocking bearing on edge 81 of bracket 48 while one end passes throughreset plunger 54 and the other end may rest on contact surface 84 ofstep-like form provided by suitably bending the free end of thermostat36. Tension spring 52 has one end engaged with a spring retaining hook78 which may be provided by slitting and bending a tongue from a part ofone wall of the guide way 76 in bracket 48. The other end of spring 52is attached to arm 50 by any suitable means, such as that shown in thedrawings, where a hook 86 is provided by an appropriately shapedpiercing in the said arm; being so attached to the bracket 48 and to thearm 50, the spring 52 by its tension biases the arm 50 from the positionshown in Figure 1 to that shown in Figure 2. The reset plunger 54 ismost conveniently made of a flat strip of insulating material such asphenolic impregnated laminated paper or fabric; it is slidinglysupported by guideway 76 and opening 72 in disc 46 and has a hole 88 forthe reception of a finger 90 shaped on one end of arm 50, whereby thesaid arm and the plunger 54 may move in unison as will also be madeclear by a comparison of Figures 1 and 2. The arm 50 is notched as at 51to afford a neck portion 92, suited to be movably supported and retainedbetween the margins 82 of bracket 48 while having a rocking bearing onedge portion 81 thereof. In order to provide a somewhat more precise andat the same time inexpensive bearing for the said arm we have found itexpedient to coin a groove 94 in the neck portion 92. We have also foundit desirable to coin a portion of one end of the arm 50 as at 96 toeliminate any burrs and to provide a smooth and well compacted contactportion for engagement with the mating contact surface 84 of thermostat36.

In making up the subassembly B, the bracket 48 is secured to disc 46 byriveting over the end of terminal stud 56 as at 66 and the tongue 68having passed through opening 72 is bent over to secure the partsagainst relative movement as before described. The reset plunger 54 isnext slipped into its guides and circuit breaker arm 50 is passedthrough the widest part of opening 70 and, with the finger 90 in placein hole 88 of reset plunger 54, the groove 94 is seated on the edge 81;the tension spring is next attached to books 78 and 86 and thesubassembly completed and ready to be placed over the open end ofhousing 20 and to be there secured by bending over the fingers 60 sothat they hold the disc 46 with its attached parts in place.

It will be noted that each component of our socket is arranged forkeying engagement in one form or another with cooperating components. Inthis way we have provided means whereby all elements having importantalignment requirements may be maintained in correct orientation Withoutthe need of highly skilled labor at assembly or, critical adjustmentthereafter. It will be further noted that once the assembly has beenmade, no moving current-carryingv parts are exposed or exposable but allare tightly housed and protected against deleterious external influencesand the only part requiring or susceptible to manipulation is theexposed end of the reset plunger 54.

When our novel socket is connected to a source of electricity and with asuitable plug in place and in position for energizing, current will passthrough terminal stud 56, bracket 48, contact breaker arm 50, thermostat36, rivet 34 and terminal member 26 to the plug (details ofwhichbeingWell known, are omitted) and thence to ground via the walls ofreceptacle 10. Should the plug be held in closed circuit position longerthan is desirable heat will be transmitted from the heating unit of theplug, by radiation and conduction, to thermostat 36 which is arrangedtovwarp, under the influence of heat, away from arm 50 which whencleared by contact surface 84 will be moved by spring 52 to the positionshown in Figure 2, and in being so moved the arm 50 will cause the resetplunger 54 to move in an outward direction. After the parts concernedhave regained normal temperature the reset plunger 54 may be movedinward by slight digital pressure and the circuit breaker restored tonormal current carrying condition. In the event of a short circuitoccurring in the receptacle such as might be caused by-the introductionof a foreign metallic body, the thermostat 36 will, by virtue of heatconsequent on its resistance to the passage of heavy currents, warp inthe same manner as' when exposed to an unduly high ambienttemperatureand thereby initiate the above described circuit breaking series ofevents.

We have found that in the case of a cigar lighter operating on 12 voltsand drawing about 100 watts that the thermostat 36 may well be made of astrip of bi-metal A" wide, .015" thick and having a free arm length ofsubstantially and that a desirable nominal composition of the bi-metalis, on the high expansion side, 79% Fe, 2% Cr and 19% Ni; While the lowexpansion side is 61% Fe and 39% Ni. We have also found it desirable toimpose a load of A1 to 1 lb. through spring 52, onto the contactsurfaces of arm 50 and thermostat 36 at 84. With such arrangements andloads, we have found that the circuit breaker will function repeatedlyand reliably with either short circuits or high ambient temperatures asthe initial cause of warping of the thermostat.

We claim:

1. In a cigar lighter having a holder in which a removable plug having aheating element is adapted to be received and manually moved into aposition to be heated; a terminal in said holder having means thereonfor engaging the plug when in such position so as to energize theheating element thereof to a normally-attained predeterminedtemperature; means defining a housing on said holder rearwardly of saidterminal; a circuit breaker mounted in said housing comprising athermally-responsive arm having a portion normally disposed in anoperative position and movable into a release position in response toexcessive temperature conditions and a movable arm having a portionresiliently urged into an inoperative position out of engagement withsaid thermally-responsive arm in response to the movement of the latterinto its release position; exposed means operatively connected with saidmovable arm Within said housing and extending outwardly therefrom formoving said movable arm portion into an operative position innormally-retained engagement with said thermallyresponsive arm portion;and means for electrically connecting said arms in series between saidterminal and a source of electrical current.

2. In a cigar lighter having a holder in which a removable plug having aheating element is adapted to be received and manually moved into aposition to be heated; a terminal, in said holder having means thereonfor engaging the plug when inv such. position so as to energize theheating element thereof to a normally-attained predeterminedtemperature; means defining a housing on said holder rearwardly of saidterminal; a circuit breaker mounted in said housing comprising a pair ofnormally interconnected. arms electrically connected in series with saidterminal, one of said arms beingoperable in response toexcessive-temperature conditions to move into a release position, theother of said arms being biased to move away from said one arm inresponse to the movement of the latter into said release position; andreset means for moving said arms back into interconnected relation afterthey have been moved apart, said reset means including an end portionextending outwardly of said housing in exposed condition soas to bemanually engaged without the necessity of removing any covering parts. 7

i 3. In a cigar lighter having a holder in which a removable plug havinga heating element is adapted to be received and manually moved into aposition to be heated; a terminal in said holder having means thereonfor engaging the plug when in such position so as to energize theheating element thereof to a normally attained predeterminedtemperature; means defining a housing on said holder rearwardlyof saidterminal; a circuit breaker mounted. in said housin comprising athermallyresponsive arm having a free end normally disposed in anoperative position and movable into a release position in response toexcessive temperature conditions, and an oscillating arm ofelectrically-conductive material having a free end resiliently urgedinto an inoperative position out of engagement with saidthermally-responsive arm in response to the movement of the latter intoits release position; exposed means operatively connected with saidoscillating arm within said housing and extending outwardly therefromfor moving the free end of said oscillating arm into an operativeposition in normally retained engagement with the free end of saidthermallyresponsive arm; and means for electrically connecting said armsin series between said terminal and a source of electrical current.

4. In a cigar lighter having a holder in which a removable plug having aheating element is adapted to be received and manually moved into aposition to be heated; a terminal in said holder having means thereonfor engaging the plug when in such position so as to energize theheating element thereof to a normally-attained predeterminedtemperature; means' defining a housing on said holder rearwardly of saidterminal; a circuit breaker mounted in said housing comprising athermostatic arm connected with said terminal and having a free endnormally disposed in an operative position and movable into a releaseposition in response to excessive-temperature conditions, a bracketmounted within the housing having means thereon for connection with asource of electrical current, a circuit breaker arm swingably mountedintermediate its ends on said bracket and spring means between saidcircuit breaker arm and said bracket for resiliently urging one end ofsaid circuit breaker arm into an inoperative position out of engagementwith said thermostatic arm in response to the movement of the latterinto its release position; and a plunger having one end slidably mountedwithin said bracket, an opposite exposed end extending outwardly of thehousing, and an aperture intermediate said ends receiving the oppositeend of said circuit breaker arm so that movement of said plungerinwardly will operate to swing the one end of said circuit breaker armagainst the action of the spring means into normally retained engagementwith the free end of said thermostatic arm after the same have movedapart.

5. A cigar lighter as defined in claim 4 wherein said bracket includesan intermediate portion having a pair of adjacent apertures of differentwidths formed therein, and wherein said circuit breaker arm has a pairof opposed notches forming a reduced intermediate portion arranged toseat within the smaller of said apertures, the larger of said aperturesbeing of a size sufficient to permit the passage of the portion of saidcircuit breaker arm adjacent said notches therethrough.

6. A cigar lighter as defined in claim 4 wherein said bracket includes apair of opposed L-shaped flanges extending from one end thereof so as toform a guideway for slidably receiving the one end of said plunger.

7. A cigar lighter as defined in claim 4 wherein said housing definingmeans comprises a tubular member extending from said holder and discs ofinsulating material disposed at the ends of said tubular member.

8. A cigar lighter as defined in claim 7 wherein the means on saidbracket for connection with a source of electrical current comprises asecond terminal extending through the other of said discs and securingsaid bracket thereto.

9. A cigar lighter as defined in claim 8 wherein said bracket includes abent portion struck therefrom so as to form said adjacent apertures,said bent portion having a projection extending through the other ofsaid discs.

10. A circuit breaker comprising a tubular housing,

discs of insulating material disposed at the ends of said housing, aterminal extending through each of said discs, a bracket having one endsecured to one of said terminals within said housing and an opposite endextending therein, said bracket including an intermediate portion havingadjacent apertures of difierent widths formed therein, a circuit breakerarm plate having notches formed in opposite edges thereof so as toprovide a reduced in- 3 termediate portion, the portion of said armplate adjacent said notches being of a width sufiicient to permit entrythereof through the larger of said bracket apertures and the width ofthe intermediate portion of said arm plate being of sufiicient size toenter the smaller of said bracket apertures so as to form a pivotal axisfor said arm plate, a spring between said bracket and said arm plateresiliently urging the latter into said smaller bracket aperture, theopposite end of said bracket having a pair of opposed L-shaped flangesextending therefrom so as to form a guideway, a plunger having one endslidably mounted within said guideway and an opposite end extendingthrough the disc through which said one terminal extends, said plungerhaving an aperture formed therein intermediate its ends, one end of saidarm plate being engaged within said plunger aperture, a thermostatic armhaving one'end portion thereof secured to the other of said terminalsand an opposite end normally positioned in retained inter-engagedrelation with the opposite end of said arm plate, the opposite end ofsaid thermostatic arm being operable to move into a release position inresponse to excessive-temperature conditions whereby said spring isoperable to move the opposite end of said arm plate away from saidthermostatic arm.

References Cited in the file of this patent UNITED STATES PATENTS2,409,917 Von Hoorn Oct. 22, 1946 2,442,693 Jackson June 1, 19482,548,825 Schwend et a1. Apr. 10, 1951 2,563,174 Kitman Aug. 7, 19512,704,318 Jorgensen et a1 Mar. 15, 1955

